Kevin Grennan created this Robot Armpit prototype. There's more good stuff about his work with robots that smell scary in this We Make Money Not Art interview and profile, in honor of The Smell of Control: Fear, Focus, Trust, which deals with smell and robotics.
It was important to me that the odours and chemicals came from within the robots and that they were an integrated means for them to communicate with the humans who would surround them. Each robot that I have augmented with a 'sweat gland' emits a particular chemical that has a specific effect on humans and the chemical has been chosen to further enable the robot's primary function.
In the case of the bomb disposal robot the 'sweat gland' releases the smell of human fear. It has been proven that humans can identify this specific smell and it tends to enhance cognitive performance in. I propose that this robot would enable surrounding humans to work more effectively and to differentiate dangerous situations from false alarms.
In the case of the picker robot. It releases a chemical called androstadienone, which is found in male sweat. This has be shown in research to effect mood in females under certain circumstances. I have speculated that this robot when used on a production line could enhance the performance of female employees in it's vicinity.